Commit Graph

81107 Commits

Author SHA1 Message Date
Vladimir Sementsov-Ogievskiy
b33b354f3a block/io: refactor save/load vmstate
Like for read/write in a previous commit, drop extra indirection layer,
generate directly bdrv_readv_vmstate() and bdrv_writev_vmstate().

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200924185414.28642-8-vsementsov@virtuozzo.com>
2020-10-05 10:59:42 +01:00
Vladimir Sementsov-Ogievskiy
fae2681add block: drop bdrv_prwv
Now that we are not maintaining boilerplate code for coroutine
wrappers, there is no more sense in keeping the extra indirection layer
of bdrv_prwv().  Let's drop it and instead generate pure bdrv_preadv()
and bdrv_pwritev().

Currently, bdrv_pwritev() and bdrv_preadv() are returning bytes on
success, auto generated functions will instead return zero, as their
_co_ prototype. Still, it's simple to make the conversion safe: the
only external user of bdrv_pwritev() is test-bdrv-drain, and it is
comfortable enough with bdrv_co_pwritev() instead. So prototypes are
moved to local block/coroutines.h. Next, the only internal use is
bdrv_pread() and bdrv_pwrite(), which are modified to return bytes on
success.

Of course, it would be great to convert bdrv_pread() and bdrv_pwrite()
to return 0 on success. But this requires audit (and probably
conversion) of all their users, let's leave it for another day
refactoring.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200924185414.28642-7-vsementsov@virtuozzo.com>
2020-10-05 10:59:42 +01:00
Vladimir Sementsov-Ogievskiy
9bb4b066cc block: generate coroutine-wrapper code
Use code generation implemented in previous commit to generated
coroutine wrappers in block.c and block/io.c

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200924185414.28642-6-vsementsov@virtuozzo.com>
2020-10-05 10:59:42 +01:00
Vladimir Sementsov-Ogievskiy
aaaa20b69b scripts: add block-coroutine-wrapper.py
We have a very frequent pattern of creating a coroutine from a function
with several arguments:

  - create a structure to pack parameters
  - create _entry function to call original function taking parameters
    from struct
  - do different magic to handle completion: set ret to NOT_DONE or
    EINPROGRESS or use separate bool field
  - fill the struct and create coroutine from _entry function with this
    struct as a parameter
  - do coroutine enter and BDRV_POLL_WHILE loop

Let's reduce code duplication by generating coroutine wrappers.

This patch adds scripts/block-coroutine-wrapper.py together with some
friends, which will generate functions with declared prototypes marked
by the 'generated_co_wrapper' specifier.

The usage of new code generation is as follows:

    1. define the coroutine function somewhere

        int coroutine_fn bdrv_co_NAME(...) {...}

    2. declare in some header file

        int generated_co_wrapper bdrv_NAME(...);

       with same list of parameters (generated_co_wrapper is
       defined in "include/block/block.h").

    3. Make sure the block_gen_c declaration in block/meson.build
       mentions the file with your marker function.

Still, no function is now marked, this work is for the following
commit.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200924185414.28642-5-vsementsov@virtuozzo.com>
[Added encoding='utf-8' to open() calls as requested by Vladimir. Fixed
typo and grammar issues pointed out by Eric Blake. Removed clang-format
dependency that caused build test issues.
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-10-05 10:59:06 +01:00
Vladimir Sementsov-Ogievskiy
21c2283ebc block: declare some coroutine functions in block/coroutines.h
We are going to keep coroutine-wrappers code (structure-packing
parameters, BDRV_POLL wrapper functions) in separate auto-generated
files. So, we'll need a header with declaration of original _co_
functions, for those which are static now. As well, we'll need
declarations for wrapper functions. Do these declarations now, as a
preparation step.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200924185414.28642-4-vsementsov@virtuozzo.com>
2020-10-05 09:35:52 +01:00
Vladimir Sementsov-Ogievskiy
f9e694cb32 block/io: refactor coroutine wrappers
Most of our coroutine wrappers already follow this convention:

We have 'coroutine_fn bdrv_co_<something>(<normal argument list>)' as
the core function, and a wrapper 'bdrv_<something>(<same argument
list>)' which does parameter packing and calls bdrv_run_co().

The only outsiders are the bdrv_prwv_co and
bdrv_common_block_status_above wrappers. Let's refactor them to behave
as the others, it simplifies further conversion of coroutine wrappers.

This patch adds an indirection layer, but it will be compensated by
a further commit, which will drop bdrv_co_prwv together with the
is_write logic, to keep the read and write paths separate.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200924185414.28642-3-vsementsov@virtuozzo.com>
2020-10-05 09:35:52 +01:00
Vladimir Sementsov-Ogievskiy
5416645fcf block: return error-code from bdrv_invalidate_cache
This is the only coroutine wrapper from block.c and block/io.c which
doesn't return a value, so let's convert it to the common behavior, to
simplify moving to generated coroutine wrappers in a further commit.

Also, bdrv_invalidate_cache is a void function, returning error only
through **errp parameter, which is considered to be bad practice, as
it forces callers to define and propagate local_err variable, so
conversion is good anyway.

This patch leaves the conversion of .bdrv_co_invalidate_cache() driver
callbacks and bdrv_invalidate_cache_all() for another day.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200924185414.28642-2-vsementsov@virtuozzo.com>
2020-10-05 09:35:52 +01:00
Philippe Mathieu-Daudé
eefffb0244 block/nvme: Replace magic value by SCALE_MS definition
Use self-explicit SCALE_MS definition instead of magic value
(missed in similar commit e4f310fe7f).

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200922083821.578519-7-philmd@redhat.com>
2020-10-05 09:35:52 +01:00
Philippe Mathieu-Daudé
fad1eb6886 block/nvme: Use register definitions from 'block/nvme.h'
Use the NVMe register definitions from "block/nvme.h" which
ease a bit reviewing the code while matching the datasheet.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200922083821.578519-6-philmd@redhat.com>
2020-10-05 09:35:52 +01:00
Philippe Mathieu-Daudé
9406e0d97e block/nvme: Drop NVMeRegs structure, directly use NvmeBar
NVMeRegs only contains NvmeBar. Simplify the code by using NvmeBar
directly.

This triggers a checkpatch.pl error:

  ERROR: Use of volatile is usually wrong, please add a comment
  #30: FILE: block/nvme.c:691:
  +    volatile NvmeBar *regs;

This is a false positive as in our case we are using I/O registers,
so the 'volatile' use is justified.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200922083821.578519-5-philmd@redhat.com>
2020-10-05 09:35:52 +01:00
Philippe Mathieu-Daudé
37d7a45abd block/nvme: Reduce I/O registers scope
We only access the I/O register in nvme_init().
Remove the reference in BDRVNVMeState and reduce its scope.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200922083821.578519-4-philmd@redhat.com>
2020-10-05 09:35:52 +01:00
Philippe Mathieu-Daudé
f68453237b block/nvme: Map doorbells pages write-only
Per the datasheet sections 3.1.13/3.1.14:
  "The host should not read the doorbell registers."

As we don't need read access, map the doorbells with write-only
permission. We keep a reference to this mapped address in the
BDRVNVMeState structure.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200922083821.578519-3-philmd@redhat.com>
2020-10-05 09:35:52 +01:00
Philippe Mathieu-Daudé
b02c01a513 util/vfio-helpers: Pass page protections to qemu_vfio_pci_map_bar()
Pages are currently mapped READ/WRITE. To be able to use different
protections, add a new argument to qemu_vfio_pci_map_bar().

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200922083821.578519-2-philmd@redhat.com>
2020-10-05 09:35:52 +01:00
Peter Maydell
469e72ab7d Block layer patches:
- Add block export infrastructure
 - iotests improvements
 - Document the throttle block filter
 - Misc code cleanups
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Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches:

- Add block export infrastructure
- iotests improvements
- Document the throttle block filter
- Misc code cleanups

# gpg: Signature made Fri 02 Oct 2020 15:36:53 BST
# gpg:                using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg:                issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream: (37 commits)
  qcow2: Use L1E_SIZE in qcow2_write_l1_entry()
  qemu-storage-daemon: Fix help line for --export
  iotests: Test block-export-* QMP interface
  iotests: Allow supported and unsupported formats at the same time
  iotests: Introduce qemu_nbd_list_log()
  iotests: Factor out qemu_tool_pipe_and_status()
  nbd: Deprecate nbd-server-add/remove
  nbd: Merge nbd_export_new() and nbd_export_create()
  block/export: Move writable to BlockExportOptions
  block/export: Add query-block-exports
  block/export: Create BlockBackend in blk_exp_add()
  block/export: Move blk to BlockExport
  block/export: Add BLOCK_EXPORT_DELETED event
  block/export: Add block-export-del
  block/export: Move strong user reference to block_exports
  block/export: Add 'id' option to block-export-add
  block/export: Add blk_exp_close_all(_type)
  block/export: Allocate BlockExport in blk_exp_add()
  block/export: Add node-name to BlockExportOptions
  block/export: Move AioContext from NBDExport to BlockExport
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2020-10-02 16:19:42 +01:00
Alberto Garcia
c508c73dca qcow2: Use L1E_SIZE in qcow2_write_l1_entry()
We overlooked these in 02b1ecfa10

Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-Id: <20200928162333.14998-1-berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
45db4bc1fc qemu-storage-daemon: Fix help line for --export
Commit 5f479a8d renamed the 'device' option of --export into
'node-name', but forgot to update the help in qemu-storage-daemon.

Fixes: 5f479a8dc086bfa42c9f94e9ab69962f256e207f
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20200930133909.58820-1-kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
f51af04cce iotests: Test block-export-* QMP interface
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20200924152717.287415-32-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
f71255228e iotests: Allow supported and unsupported formats at the same time
This is useful for specifying 'generic' as supported (which includes
only writable image formats), but still excluding some incompatible
writable formats.

It also removes more lines than it adds.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20200924152717.287415-31-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
81b6b2bc1a iotests: Introduce qemu_nbd_list_log()
Add a function to list the NBD exports offered by an NBD server.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20200924152717.287415-30-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
91efbae938 iotests: Factor out qemu_tool_pipe_and_status()
We have three almost identical functions that call an external process
and return its output and return code. Refactor them into small wrappers
around a common function.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20200924152717.287415-29-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
443127e81b nbd: Deprecate nbd-server-add/remove
These QMP commands are replaced by block-export-add/del.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20200924152717.287415-28-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
5b1cb49704 nbd: Merge nbd_export_new() and nbd_export_create()
There is no real reason any more why nbd_export_new() and
nbd_export_create() should be separate functions. The latter only
performs a few checks before it calls the former.

What makes the current state stand out is that it's the only function in
BlockExportDriver that is not a static function inside nbd/server.c, but
a small wrapper in blockdev-nbd.c that then calls back into nbd/server.c
for the real functionality.

Move all the checks to nbd/server.c and make the resulting function
static to improve readability.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-27-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
30dbc81d31 block/export: Move writable to BlockExportOptions
The 'writable' option is a basic option that will probably be applicable
to most if not all export types that we will implement. Move it from NBD
to the generic BlockExport layer.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-26-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
8cade320c8 block/export: Add query-block-exports
This adds a simple QMP command to query the list of block exports.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-25-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
331170e073 block/export: Create BlockBackend in blk_exp_add()
Every export type will need a BlockBackend, so creating it centrally in
blk_exp_add() instead of the .create driver callback avoids duplication.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-24-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
37a4f70cea block/export: Move blk to BlockExport
Every block export has a BlockBackend representing the disk that is
exported. It should live in BlockExport therefore.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-23-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
1a9f7a804f block/export: Add BLOCK_EXPORT_DELETED event
Clients may want to know when an export has finally disappeard
(block-export-del returns earlier than that in the general case), so add
a QAPI event for it.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20200924152717.287415-22-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
3c3bc462ad block/export: Add block-export-del
Implement a new QMP command block-export-del and make nbd-server-remove
a wrapper around it.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-21-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
3859ad36f0 block/export: Move strong user reference to block_exports
The reference owned by the user/monitor that is created when adding the
export and dropped when removing it was tied to the 'exports' list in
nbd/server.c. Every block export will have a user reference, so move it
to the block export level and tie it to the 'block_exports' list in
block/export/export.c instead. This is necessary for introducing a QMP
command for removing exports.

Note that exports are present in block_exports even after the user has
requested shutdown. This is different from NBD's exports where exports
are immediately removed on a shutdown request, even if they are still in
the process of shutting down. In order to avoid that the user still
interacts with an export that is shutting down (and possibly removes it
a second time), we need to remember if the user actually still owns it.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-20-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
d53be9ce55 block/export: Add 'id' option to block-export-add
We'll need an id to identify block exports in monitor commands. This
adds one.

Note that this is different from the 'name' option in the NBD server,
which is the externally visible export name. While block export ids need
to be unique in the whole process, export names must be unique only for
the same server. Different export types or (potentially in the future)
multiple NBD servers can have the same export name externally, but still
need different block export ids internally.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-19-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
bc4ee65b8c block/export: Add blk_exp_close_all(_type)
This adds a function to shut down all block exports, and another one to
shut down the block exports of a single type. The latter is used for now
when stopping the NBD server. As soon as we implement support for
multiple NBD servers, we'll need a per-server list of exports and it
will be replaced by a function using that.

As a side effect, the BlockExport layer has a list tracking all existing
exports now. closed_exports loses its only user and can go away.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-18-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
a6ff798966 block/export: Allocate BlockExport in blk_exp_add()
Instead of letting the driver allocate and return the BlockExport
object, allocate it already in blk_exp_add() and pass it. This allows us
to initialise the generic part before calling into the driver so that
the driver can just use these values instead of having to parse the
options a second time.

For symmetry, move freeing the BlockExport to blk_exp_unref().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-17-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
b6076afcab block/export: Add node-name to BlockExportOptions
Every block export needs a block node to export, so add a 'node-name'
option to BlockExportOptions and remove the replaced option 'device'
from BlockExportOptionsNbd.

To maintain compatibility in nbd-server-add, BlockExportOptionsNbd needs
to be wrapped by a new type NbdServerAddOptions that adds 'device' back
because nbd-server-add doesn't use the BlockExportOptions base type at
all (so even without changing it to a 'node-name' option in
block-export-add, this compatibility code would be necessary).

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-16-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
8612c68673 block/export: Move AioContext from NBDExport to BlockExport
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-15-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
c69de1bef5 block/export: Move refcount from NBDExport to BlockExport
Having a refcount makes sense for all types of block exports. It is also
a prerequisite for keeping a list of all exports at the BlockExport
level.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-14-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
dbc9e94a23 nbd/server: Simplify export shutdown
Closing export is somewhat convoluted because nbd_export_close() and
nbd_export_put() call each other and the ways they actually end up being
nested is not necessarily obvious.

However, it is not really necessary to call nbd_export_close() from
nbd_export_put() when putting the last reference because it only does
three things:

1. Close all clients. We're going to refcount 0 and all clients hold a
   reference, so we know there is no active client any more.

2. Close the user reference (represented by exp->name being non-NULL).
   The same argument applies: If the export were still named, we would
   still have a reference.

3. Freeing exp->description. This is really cleanup work to be done when
   the export is finally freed. There is no reason to already clear it
   while clients are still in the process of shutting down.

So after moving the cleanup of exp->description, the code can be
simplified so that only nbd_export_close() calls nbd_export_put(), but
never the other way around.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200924152717.287415-13-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
00917172a6 qemu-nbd: Use blk_exp_add() to create the export
With this change, NBD exports are now only created through the
BlockExport interface. This allows us finally to move things from the
NBD layer to the BlockExport layer if they make sense for other export
types, too.

blk_exp_add() returns only a weak reference, so the explicit
nbd_export_put() goes away.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-12-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
d794f7f372 nbd: Remove NBDExport.close callback
The export close callback is unused by the built-in NBD server. qemu-nbd
uses it only during shutdown to wait for the unrefed export to actually
go away. It can just use nbd_export_close_all() instead and do without
the callback.

This removes the close callback from nbd_export_new() and makes both
callers of it more similar.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200924152717.287415-11-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
fefee85da0 nbd: Add writethrough to block-export-add
qemu-nbd allows use of writethrough cache modes, which mean that write
requests made through NBD will cause a flush before they complete.
Expose the same functionality in block-export-add.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-10-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
1c8222b014 nbd: Add max-connections to nbd-server-start
This is a QMP equivalent of qemu-nbd's --shared option, limiting the
maximum number of clients that can attach at the same time.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200924152717.287415-9-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
9b562c646b block/export: Remove magic from block-export-add
nbd-server-add tries to be convenient and adds two questionable
features that we don't want to share in block-export-add, even for NBD
exports:

1. When requesting a writable export of a read-only device, the export
   is silently downgraded to read-only. This should be an error in the
   context of block-export-add.

2. When using a BlockBackend name, unplugging the device from the guest
   will automatically stop the NBD server, too. This may sometimes be
   what you want, but it could also be very surprising. Let's keep
   things explicit with block-export-add. If the user wants to stop the
   export, they should tell us so.

Move these things into the nbd-server-add QMP command handler so that
they apply only there.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-8-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
b57e4de079 qemu-nbd: Use raw block driver for --offset
Instead of implementing qemu-nbd --offset in the NBD code, just put a
raw block node with the requested offset on top of the user image and
rely on that doing the job.

This does not only simplify the nbd_export_new() interface and bring it
closer to the set of options that the nbd-server-add QMP command offers,
but in fact it also eliminates a potential source for bugs in the NBD
code which previously had to add the offset manually in all relevant
places.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200924152717.287415-7-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
060102ad65 qemu-storage-daemon: Use qmp_block_export_add()
No reason to duplicate the functionality locally, we can now just reuse
the QMP command block-export-add for --export.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200924152717.287415-6-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
56ee86261e block/export: Add BlockExport infrastructure and block-export-add
We want to have a common set of commands for all types of block exports.
Currently, this is only NBD, but we're going to add more types.

This patch adds the basic BlockExport and BlockExportDriver structs and
a QMP command block-export-add that creates a new export based on the
given BlockExportOptions.

qmp_nbd_server_add() becomes a wrapper around qmp_block_export_add().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200924152717.287415-5-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
143ea7670c qapi: Rename BlockExport to BlockExportOptions
The name BlockExport will be used for the struct containing the runtime
state of block exports, so change the name of export creation options.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200924152717.287415-4-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
5daa6bfd8e qapi: Create block-export module
Move all block export related types and commands from block-core to the
new QAPI module block-export.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200924152717.287415-3-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Kevin Wolf
8760366cdb nbd: Remove unused nbd_export_get_blockdev()
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200924152717.287415-2-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Dr. David Alan Gilbert
da16f4b867 qemu-io-cmds: Simplify help_oneline
help_oneline is declared and starts as:

  static void help_oneline(const char *cmd, const cmdinfo_t *ct)
  {
      if (cmd) {
          printf("%s ", cmd);
      } else {
          printf("%s ", ct->name);
          if (ct->altname) {
              printf("(or %s) ", ct->altname);
          }
      }

However, there are only two routes to help_oneline being called:

   help_f -> help_all -> help_oneline(ct->name, ct)

   help_f -> help_onecmd(argv[1], ct)

In the first case, 'cmd' and 'ct->name' are the same thing,
so it's impossible for the if (cmd) to be false and then validly
print ct->name - this is upsetting gcc
( https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96739 )

In the second case, cmd is argv[1] and we know we've got argv[1]
so again (cmd) is non-NULL.

Simplify help_oneline by just printing cmd.
(Also strengthen argc check just to be pedantic)

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20200824102914.105619-1-dgilbert@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Alberto Garcia
8e7b122bf8 docs: Document the throttle block filter
This filter was added back in 2017 for QEMU 2.11 but it was never
properly documented, so let's explain how it works and add a couple of
examples.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-Id: <20200921173016.27935-1-berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00
Thomas Huth
0f3231bfb5 tests/check-block: Do not run the iotests with old versions of bash
macOS is shipped with a very old version of the bash (3.2), which
is currently not suitable for running the iotests anymore (e.g.
it is missing support for "readarray" which is used in the file
tests/qemu-iotests/common.filter). Add a check to skip the iotests
in this case - if someone still wants to run the iotests on macOS,
they can install a newer version from homebrew, for example.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20200918153514.330705-1-thuth@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-10-02 15:46:40 +02:00